1. Field of the Invention
The present invention relates to a golf ball having a dimple arrangement made by a new divisional composition of the spherical outer surface, the golf ball which has the characteristic of fixed landing point after flying with a high trajectory and increased carry distance.
2. Description of the Related Art
In a golf ball, the dimples are arranged by dividing the outer surface into the faces of a spherical polyhedron with the great circle paths. There are many kinds of divisional composition, for example, spherical tetrahedron composed of four spherical triangles, spherical hexahedron composed of six spherical squares, spherical octahedron composed of eight spherical triangles, spherical dodecahedron composed of twelve spherical pentagons, spherical icosahedron composed of twenty spherical triangles. Besides aforementioned divisional composition, the dimples are arranged by further divided polyhedron such as spherical icosidodecahedron composed of spherical twenty triangles and twelve pentagons, and spherical cubeoctahedron composed of six squares and eight triangles. All kinds of the dimple arrangement of the divisional compositions are superimposed each other on the surface of a sphere in the same diameter.
The new dimple arrangements of the golf balls are continuously made by the new divisional compositions in spite of the same situation. The reason is that the surface area of the polygon of polyhedron is different each other in accordance with the kind of divisional composition. So the dimples can be arranged differently in size, depth and shape in the surface of a golf ball. As a result, the aerodynamic characteristic is different between the dimple arrangements by the divisional compositions. And, when the dimples being arranged in the surface of the golf ball by the aforementioned divisional compositions, even in a same polygon of polyhedron, the symmetrically arranged dimples have a good aerodynamic characteristic compare to the non-symmetrically arranged dimples.
The reason is that the golf ball has the aerodynamic stability and has no sway at a low-speed area from the apex of trajectory to the landing point. The dimple coverage which is an important factor for obtaining the sufficient aerodynamic lift that should be more than 76% about the entire surface of a golf ball. But the dimple size is more important factor than others for controlling the flight characteristics. The pressure drag of larger dimples is enlarged in a high-speed area from launching to the apex of trajectory comparing to the small dimples. On the contrary, in a low-speed area from apex to the landing point, the pressure drag of small dimples is increased. But, in case of the average diameter of small dimples is under the 0.140″, that is, more than 500 dimples are arranged on the surface of golf ball (the depth of dimples are 0.006″˜0.0065″) which has a lower trajectory and increased the pressure drag in a low-speed area, so the carry distance is decreased. On the contrary, the average diameter of larger dimples is more than 0.160″, that is, less than 350 dimples are arranged on the surface of golf ball (the depth of dimples are 0.006″˜0.0065″) which has a higher trajectory and rapidly increased the pressure drag in a high-speed area, so the carry distance is decreased. Therefore, recently the dimples are arranged in a combination of large and small diameter. But the larger dimples mostly controlled the character of flight of the golf ball, because the occupied portion of the area of larger dimple is quite larger than the small one on the surface of the golf ball.
Accordingly, new divisional compositions of the spherical outer surface of a golf ball are required to obtain stable and uniform landing point and increase the carrying distance, with the requisition for research on effective arrangements of dimples on the divided surface of the golf ball.